Bean Plant Growth

Introduction:

For "The Story of the Seed" lab, we decided to test whether or not the color of light effected the growth of the plant.  We filtered light through blue, yellow, and clear saran wrap.  Our light source was one florescent lamp above the three plants.  Our hypothesis is if the color of light effects the growth of the plant, then the blue filtered light will increase the plant's growth speed. We chose the blue filtered light because darker colors absorb more light than lighter colors.  Our theory was that since plants grow towards sunlight, it would do the same towards florescent light.

Methods: 

The first part of the experiment is to gather all the materials: 3 plastic cups, half a cup filled with dirt, 9 seeds(of your choice), blue, yellow, and clear saran wrap, rubber bands, water, a graduated cylinder, a ruler, a lamp, and a florescent light bulb.

Step 1: Gather 3 cups and poke 2 holes in the bottom of the each cup so the water can drain

Step 2: Fill each cup half way full of dirt.

Step 3: Dig a small hole and place 3 seeds in each cup

Step 4: Cover the seeds back up with dirt

Step 5: Moisten the dirt with 80 mL of water

Step 6: Cover one cup with any color saran wrap

Step 7: Rubber band the top so the saran wrap is secure

Step 8: Repeat steps 6 and 7 with each cup and different colors on every cup

Step 9: Cut 1- 1/2 inch slits in the top of each cups saran wrap

Step 10: Place cups in a dark area(such as a closet) so that the only light it receives is from the florescent light

Step 11: Turn on light bulb and position the plants so that each one gets the same amount of light

Step 12: Leave the plants in the closet and check and record changes every day for seven days

Step 13: Water them every other day

Observation:

Day 1: So far no change has occurred. The soil is still moist from the 80 mL of water added earlier in the day, and each plant is getting the same amount of sunlight.

Day 2: There is possible sprouting in the yellow lighting. In the blue lighting the seed has split open but nothing has sprouted. The clear lighting still has no germination.

Day 3: In the blue and yellow cup, the seed has made its was to the top of the dirt. There is green starting to sprout from the yellow cup but no significant sprouting. There is still no sign of germination is the clear lighting. Also, we added 20 mL of water to each cup.

       
 

  

Day 4: All three seeds have sprouted; the yellow cups stems are taller(about 2cm), but there are more sprouted in the blue cup. The seeds have come to the surface of the dirt in all three cups, so the question is, are they reaching for the sunlight? or is the dirt sinking from the water?

                                                          

                                               

           

Day 5: All the seeds have come up through the holes in the colored lighting. There is still one seed in the clear lighting that hasn't sprouted yet. Each day, the plants increase in size. At this point, it looks as though the yellow light causes the plant to grow faster, but the blue light is not far behind. We added 20mL of water today as well.

The stem lengths are 6.5cm, 5.5cm, and 5cm

The stem lengths are 9cm, 6.5. and 4cm

The stem length are 5.5cm and 5cm
Day 6: The plants have grown tremendously. Now, the blue lighting's plants have lengths of 11.5, 13.6, and 11.5 centimeters. The yellow lighting's plants have lengths of 13.5, 13.4, and 13.2 centimeters. The final seed in the clear lighting finally sprouted giving the plants lengths of 13.5, 13.4, and 2.2 centimeters.

 Day 7: On each plant, the beans on the stem have split open and leaves have started to grow. Yesterday, the yellow plant had a significant length lead against the others. Today however, that lead is only by a few centimeters, but it is still the tallest of the three. We also added 20 mL of water today.Stem Lengths: 21, 20.5, & 20 centimeters

Stem Lengths:  24.4, 23, & 21.5 centimeters

Stem Lengths: 23, 22.1 & 11 centimeters
Results and Data Analysis:  After seven days of observation, we conclude that the yellow filter increased the growth of the plant the most. I believe that this happened because this is closer to the color to the light that is given off by the sun. I also observed that they stayed even in height until day five and even then they were pretty close in height, not until day six. On day six you really started to see which light filter effected the plants growth.

Conclusion: After our experiment, we found out that our results supported another hypothesis.  We hypothesized that the blue light filter would increase the growth rate, but as it turns out, the yellow light filter increased it the most.  The blue light filter was only a few centimeters behind, followed by our control variable. But, we can not draw a firm conclusion, therefore, more trials are recommended.